The document discusses the Global Positioning System (GPS), which is a satellite-based navigation system developed by the U.S. Department of Defense. GPS uses a constellation of 24 satellites that continuously transmit radio signals, allowing GPS receivers to determine their location by calculating the time delay of signals received from multiple satellites. The GPS receiver measures the distance to each satellite by determining how long it takes the radio signal to travel from the satellite to the receiver, then uses trilateration to calculate the user's exact position based on the distances to several satellites. GPS has many applications including aviation, marine, automotive navigation, surveying, and more.

1. Humans
have
always
been
Interested
in knowing
where
Things
are………..

2. Global Positioning
System(GPS)

3. WHAT IS GPS?
• Satellite based navigation
system.
• Based on a constellation of
about 24 satellites
• Developed by the United States
Department of Defense (DOD)

4. How GPS come ???
Being crucial of navigation and
positioning process, its difficult and
slow in the earlier days.
Then U.S department of Defense
decided that military should have a
precise form of worldwide positing.
The result is the Global Positioning
System.

5. HOW GPS DETERMINES A LOCATION
Things which need to be
determined:
 Current Locations of GPS
Satellites
 The Distance Between
Receiver’s Position and the
GPS Satellites

6. To Locate the
Location

7. Measuring Distance
Explanation
Satellite
portion:
generate
C/A codes
as PRN
sequence.
Receiver Portion
 Compute C/A’s
replica code.
 Transmit a
PRN, keep
codes in
memory
Done by
using auto
correlation
function of
the received
signal.

8. Accurate Measurements of
GPS
Current Time Satellite Position Time Delay

9. GPS Signals & Frequencies
 Signals:
 Coarse/Acquisition code
 Precision code
 Navigation message
 Almanac
 Data updates
 Frequencies:
 L1 1575.42 MHz
 L2 1227.60 MHz
 L3 1381,05 MHz
 L4 1379.913 MHz
 L5 1176.45 MHz

10. Impacts of Cross-Correlation
on Acquisition Performance
 Actually a cross-correlation disturbs the acquisition
performance:
 Inaccurate doppler frequency
 Code delay
 User position estimation

11. Aviation
• Cost effective solution
• Increase the safety and efficiency
Survey & mapping
• Accuracy
• Reliability
• Interoperability
Application

12. Space
• Navigation solutions
• Altitude solutions
• Timing solutions & etc.
Marine
• saving navigators time and fuel.
• navigation information to boaters.
• Increases safety and security.

13. Rail
• improved safety of trains and
maintenance crews.
• Increased capacity and efficiency
• Time synchronization for
communication systems
Agriculture
• soil sampling, collection, analysis to
suit specific areas.
• work with low visibility.
• minimizes redundancy, maximum
ground coverage

14. MILITARY
• Target tracking
• Search and Rescue
Roads & Highways
• Higher levels of safety and mobility
for surface transportation
• Increased efficiencies reduced
costs

15. Environm
ent
Public
Safety &
Disaster
Relief
Science
Timing Tracking
Application

16. Future Technology
GPS wrist
Bands
Positioning
Head Gear
Autonomous
Tractors

17. THANKS!
Any questions?